Description

Simple

A medication used to treat serious cases of low blood pressure, often during surgery when anesthesia is used and leads to low blood pressure.

Clinical

An alpha-1 adrenergic antagonist used in the management of hypotension, generally in the surgical setting associated with the use of anesthetics.

Overview

Phenylephrine is an alpha-1 adrenergic receptor agonist used to treat hypotension,[6,8] dilate the pupil,[7] and induce local vasoconstriction.[1] The action of phenylephrine, or neo-synephrine, was first described in literature in the 1930s.[2]

Phenylephrine was granted FDA approval in 1939.[7]

Pharmacology

Indication

Phenylephrine injections are indicated to treat hypotension caused by shock or anesthesia,[6, Read more

Pharmacodynamic

Phenylephrine is an alpha-1 adrenergic agonist that raises blood pressure,[6, Read more

Mechanism of action

Phenylephrine is an alpha-1 adrenergic agonist that mediates vasoconstriction[1] and mydriasis[ Read more

Absorption

Phenylephrine is 38% orally bioavailable.[3] Clinically significant systemic absorption of ophth... Read more

Protein binding

Data regarding the protein binding of phenylephrine in serum is not readily available.[6, Read more

Volume of distribution

The volume of distribution of phenylephrine is 340L.[6, Read more

Clearance

Phenylephrine has an average clearance of 2100mL/min.[6, Read more

Half life

Intravenous phenylephrine has an effective half life of 5 minutes and an elimination half life of 2.5 hours.[ Read more

Route of elimination

86% of a dose of phenylephrine is recovered in the urine[3] with 16% as the unmetabolized drug,... Read more

Toxicity

Patients experiencing and overdose may present with headache, hypertension, reflex bradycardia, tingling limbs, cardiac arrhythmias, and a feeling of fullness in the head.[ Read more

Adverse Effects

Contraindications

  • Route:
    • Intramuscular
    • Subcutaneous
  • Dose Form:
    • Injection
  • Regions: US
  • Patient Conditions:
      • Name: Severe Hypertension
      • Drugbank Id: DBCOND0058109
      • Modification Of:
        • Base:
          • Name: Hypertension
          • Drugbank Id: DBCOND0020037
        • Severity:
          • Includes:
            • severe
  • Route:
    • Intramuscular
    • Subcutaneous
  • Dose Form:
    • Injection
  • Regions: US
  • Patient Conditions:
      • Name: Ventricular Tachycardia
      • Drugbank Id: DBCOND0031960
  • Route:
    • Ophthalmic
  • Regions: US
  • Patient Conditions:
      • Name: Thyrotoxicosis
      • Drugbank Id: DBCOND0021770
  • Route:
    • Ophthalmic
  • Regions: US
  • Patient Conditions:
      • Name: Hypertension
      • Drugbank Id: DBCOND0020037
  • Route:
    • Ophthalmic
  • Hypersensitivity:
    • false
  • Regions: US
  • Route:
    • Ophthalmic
  • Regions: US
  • Age Groups:
    • pediatric
  • Below Age:
    • Amount: 1
    • Unit: year

Food Interactions

  • Take without regard to meals.

Interactions

Type in a drug name to check for interaction with Phenylephrine
Type a drug name in the box above to get started
  • Paracetamol(acetaminophen)
  • Paxil(paroxetine)
  • Pamelor(nortriptyline)
  • Panadol(acetaminophen)
  • Patanol(olopatadine ophthalmic)
  • Pataday(olopatadine ophthalmic)
  • Parnate(tranylcypromine)
  • Pazeo(olopatadine ophthalmic)
(R)-warfarin
The metabolism of (R)-warfarin can be increased when combined with Phenylephrine.
1-(3-Mercapto-2-Methyl-Propionyl)-Pyrrolidine-2-Carboxylic Acid
The risk or severity of hypertension can be increased when Phenylephrine is combined with 1-(3-Mercapto-2-Methyl-Propionyl)-Pyrrolidine-2-Carboxylic Acid.
1-benzylimidazole
The risk or severity of hypertension can be increased when Phenylephrine is combined with 1-benzylimidazole.
2,5-Dimethoxy-4-ethylamphetamine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 2,5-Dimethoxy-4-ethylamphetamine.
2,5-Dimethoxy-4-ethylthioamphetamine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 2,5-Dimethoxy-4-ethylthioamphetamine.
3-isobutyl-1-methyl-7H-xanthine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 3-isobutyl-1-methyl-7H-xanthine.
3,5-diiodothyropropionic acid
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 3,5-diiodothyropropionic acid.
3,5-Diiodotyrosine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 3,5-Diiodotyrosine.
4-Bromo-2,5-dimethoxyamphetamine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 4-Bromo-2,5-dimethoxyamphetamine.
4-Methoxyamphetamine
The metabolism of Phenylephrine can be decreased when combined with 4-Methoxyamphetamine.
5-methoxy-N,N-dimethyltryptamine
The risk or severity of hypertension can be increased when Phenylephrine is combined with 5-methoxy-N,N-dimethyltryptamine.
6-O-benzylguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 6-O-benzylguanine.
7-Deazaguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 7-Deazaguanine.
7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline
7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline may increase the hypertensive activities of Phenylephrine.
7,9-Dimethylguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 7,9-Dimethylguanine.
8-azaguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 8-azaguanine.
8-chlorotheophylline
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 8-chlorotheophylline.
9-Deazaguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 9-Deazaguanine.
9-Methylguanine
The risk or severity of adverse effects can be increased when Phenylephrine is combined with 9-Methylguanine.
Abaloparatide
The risk or severity of adverse effects can be increased when Phenylephrine is combined with Abaloparatide.
8 References
  1. 1 . Richards E, Maani CV: Phenylephrine .PubMed: 30521222
  2. 2 . Prescott F: CLINICAL EVALUATION OF THE PRESSOR ACTIVITY OF METHEDRINE, NEO-SYNEPHRINE, PAREDRINE, AND PHOLEDRINE. Br Heart J. 1944 Oct;6(4):214-20. doi: 10.1136/hrt.6.4.214.PubMed: 18609981
  3. 3 . Kanfer I, Dowse R, Vuma V: Pharmacokinetics of oral decongestants. Pharmacotherapy. 1993 Nov-Dec;13(6 Pt 2):116S-128S; discussion 143S-146S.PubMed: 7507589
  4. 4 . Bairam AF, Rasool MI, Alherz FA, Abunnaja MS, El Daibani AA, Gohal SA, Alatwi ES, Kurogi K, Liu MC: Impact of SULT1A3/SULT1A4 genetic polymorphisms on the sulfation of phenylephrine and salbutamol by human SULT1A3 allozymes. Pharmacogenet Genomics. 2019 Jul;29(5):99-105. doi: 10.1097/FPC.0000000000000371.PubMed: 31145702
  5. 5 . Gelotte CK, Zimmerman BA: Pharmacokinetics, safety, and cardiovascular tolerability of phenylephrine HCl 10, 20, and 30 mg after a single oral administration in healthy volunteers. Clin Drug Investig. 2015 Sep;35(9):547-58. doi: 10.1007/s40261-015-0311-9.PubMed: 26267590
  6. 6 . FDA Approved Drug Products: Phenylephrine Solution for Intravenous Injection Link
  7. 7 . FDA Approved Drug Products: Phenylephrine Ophthalmic Solution Link
  8. 8 . FDA Approved Drug Products: Phenylephrine Intravenous Injection (Ready to Use) Link